A teen slugged a Brooklyn police officer in the face, but the cop took it easy on her and decided not to haul her in on a felony charge, law enforcement sources said.

Diamond Forrest, 17, repaid the kindness by gloating about it on social media — and admitting to The Post that she hates cops.

The unidentified housing officer was among several cops who responded to an apartment in East New York, where the 5-foot-4, 170-pound teen was “acting in a violent and threatening manner,” the sources said.